I think I might have come up with a better solution for the crushed blacks/whites. Going back to the The Empire Strikes Back frame with a color correction model I calibrated on a frame of Star Wars, I had the following problem giving the frame a darker grading:

Semi-Specialised Edition V2.2:

This is what I got:

The source frame suffers from crushed whites, so the model could not correctly estimate the colors in those areas, resulting in artifacts.

This time I decided to upgrade the image with a new algorithm I developed to estimate what an image with a higher color depth would look like, and use that for the color correction as a source frame. The source frame looks identical on the surface, but when I color correct it now I get this:

I think this looks much better.